Here's Another Important Reason to Get the Whooping Cough Vaccine During Pregnancy

If you’re nearing the end of your second trimester, your doctor has likely discussed giving you the Tdap booster vaccine to protect your baby from whooping cough (a.k.a. pertussis). Experts strongly recommend all expecting women get the this vaccine between weeks 27 and 36 of pregnancy to protect newborns from whooping cough. Now a new study, published in Pediatrics, has found that doing so is extremely effective at protecting babies from this highly contagious and potentially deadly disease for an entire year after birth.

What the study looked at

Researchers looked at 148,981 full-term infants born in a Northern California hospital between 2010 and 2015. They noted whether the newborns’ moms had received the Tdap vaccine during pregnancy and followed the babies for a year, noting if and when they received their own childhood DTaP shots (the vaccine that protects against pertussis). The authors then assessed the effectiveness of the Tdap vaccination during pregnancy at protecting babies against pertussis at 2 months and 1 year of life.

What it found

Babies whose moms received the Tdap vaccine during pregnancy were 91 percent less likely to contract whooping cough during the first two months of life and 69 percent less likely to become infected in the first year of life. That’s excellent news, since babies can only receive their first dose of the DTaP vaccine at 2 months of age; before then, they rely on antibodies passed from their moms in utero for protection.

The Tdap vaccine even appeared to offer babies better protection against pertussis after little ones received their own DTaP vaccinations.

"The strategy of immunizing pregnant women to boost maternal antibody transfer appears to be more effective for protecting young infants against pertussis than are attempts at 'cocooning,' in which mothers and other persons in close contact with newborns are vaccinated after the birth," said senior study author Nicola P. Klein, M.D., in a statement.

The authors noted that the number of moms who received the Tdap vaccine during pregnancy increased from less than 1 percent in 2010 to over 87 percent by 2015 following a 2013 recommendation from the Centers for Disease Control and Prevention (CDC) that all pregnant women receive the Tdap vaccine, regardless of vaccination history.

What this study means for expecting moms

Whooping cough is extremely contagious, and rates of pertussis have been on the rise in recent years. Infection with this bacterium in the first year of life can result in pneumonia, hospitalization, and even death for babies. Even if you were vaccinated before conceiving, if you don’t receive a booster dose during pregnancy your baby’s immunity wanes substantially six weeks after birth.

This study boosts the basis for recommendations by experts at both the CDC and the American Congress of Obstetricians and Gynecologists (ACOG) to get the vaccine between 27 and 36 weeks, ideally on the earlier side. Many previous studies have shown that the Tdap vaccine is safe for women and their babies during pregnancy.

“Maternal Tdap administered during pregnancy was highly effective at protecting infants against pertussis prior to their first dose of DTaP,” said Klein. "The results of this study demonstrate that maternal Tdap administered during pregnancy provides the best protection against pertussis, which strongly supports ACIP's current recommendation to administer Tdap during each pregnancy.”

Keep in mind, too, that although your Tdap vaccine does protect your baby, it’s still essential to get your baby the full DTaP vaccine on schedule — at 2, 4, and 6 months of age — to ensure she’s fully protected from whooping cough.